1. They bring a friend.
Did you invite your friend? No, because you’d never bring a friend on a date. If the person you’re meting shows up with a buddy, or says “Hey, I might invite so & so to join us,” he or she obviously isn’t too concerned with spending romantic alone time with you.

2. They don’t offer to pay/let you pay.
In general, if you’re unsure of whether or not you’re on a date, having someone offer to pay is usually a pretty good indicator that it is a date. Otherwise, the manner with which the bill is handled can tell you a lot.

Some examples:
Wordlessly grabbing the check when it comes and putting down a card: date.
“Okay, let’s see, you owe $13.50.” Not a date.

When you offer to pay the bill.
“Thank you! Next time’s on me/let me buy you a drink.” Date.
“What? No. Stop. Here’s $13 bucks, I need 7 back.” Not a date.

3. They Talk About Their Love Life
When you’re on a date, chances are, you won’t bring up your work crush, or that person you’re flirting with on GChat. If your “date” brings this up, consider yourself warned: if they were into you, the conversation would focus on you, instead some other crush they’re harboring.

4. They’re relaxed around you… a little too relaxed.
Even the most casual people will take do a little something “more” to get ready for a date they’re excited about. For some, this means carefully selecting an outfit, thinking of conversation topics, carefully applying make-up. For others, this means simply taking a shower. But most people do something.

If your date shows up disheveled, un-showered, and distracted, there’s a possibility they haven’t spent the past two hours mentally and physically prepping for this date. Use this as a clue, and then pay extra attention to their behavior. Are they sitting up straight, engaging with you, and clearly putting in a lot of effort? Or are they slouching, burping, and generally not making any sort of an effort?

This is a tricky one because some people have very laissez-faire personalities. But most everyone behaves differently on a date than when hanging out with friends: how much your date appears to be “trying” can be a good indicator as to whether he or she thinks this is a romantic rendezvous or a casual hang out.

5. You Don’t Know If They’re Interested At The End
If a date goes well, most people will want to make that clear. If he or she isn’t brave enough to “make a move,” they’ll often say something to convey their interest (“I had a really great time.” “Let me know if you ever want to hit up that sushi bar!”).

Friend dates end much more casually: a sigh, a “Well, I better get home.”, a loose hug, and a vague promise to do this again soon.

Bottom line: if you have literally no idea of a person’s interest level after spending time alone with them, it doesn’t even matter if it was a date or not because they’re clearly not interested. Bummer, but now you know, and can move on to someone who’ll be completely stoked to go on a (definite, obvious) date with you.